While my NS36 was on the hard in the Spring, I cleaned up the prop and painted it. While I was painting, I rotated the shaft. It made a rubbing sound which I didn’t think much about. I’ve had the prop shaft and cutlass bearing replaced, and over the winter I had the transmission rebuilt. It got me thinking, what is the lubricant for the shaft tube in the hull? Is it just seawater?
Yes, it is seawater lubrication at your cutlass bearing and stuffing box.
Welcome to the community, Greg. Good answer for Bob.
Bob, if you ever get a chance to look closely at a cutlass bearing before installing it, you’ll notice that it’ll have grooves running the length of the interior rubber lining. Those are to conduct the seawater along the full length of the bearing.
– Bob
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To the point about the seawater being the lubricant: when you’re painting your strut and shaft, it is easy to clog those grooves with paint if you don’t realize they are there and should be open. Fortunately, at the lower RPMs at which most of us usually operate, a submerged bearing doesn’t need a lot of flow to prevent damage.
Dan Weinstein
Look Farther, 30C #205
East Greenwich RI
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